Transverse flux electrical machine rotor

ABSTRACT

A rotatable transverse flux electrical machine (TFEM) comprising a stator portion and a rotor portion operatively disposed inside the stator portion is described therein, the rotor portion comprising a plurality of magnets and concentrators alternatively affixed in a cylindrical arrangement to a non-magnetic magnets-and-concentrators supporting frame, the non-magnetic magnets-and-concentrators supporting frame being operatively secured to an axial shaft concentrically aligned with a rotational axis of the rotor portion.

CROSS-REFERENCES

The present invention relates to, claims priority from and is anon-provisional application of U.S. Provisional Patent Application No.61/714,869, filed Oct. 17, 2012, entitled TRANSVERSE FLUX ELECTRICALMACHINE ROTOR, which is incorporated herein by reference in itsentirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates generally to transverse flux electrical machines.The present invention more specifically relates to transverse fluxalternators and motors assembly.

2. Description of the Related Art

Alternators and motors are used in a variety of machines and apparatusesto produce electricity from mechanical movements. They find applicationsfor energy production and transportation, to name a few. Alternators andmotors can use Transverse Flux Permanent Magnet (TFPM) technologies.

Transverse flux machines with permanent magnet excitation are known fromthe literature, such as the dissertation by Michael Bork, Entwicklungand Optimierung einer fertigungsgerechten Transversalfluβmaschine[Developing and Optimizing a Transverse Flux Machine to Meet ProductionRequirements], Dissertation 82, RWTH Aachen, Shaker Verlag Aachen,Germany, 1997, pages 8 ff. The circularly wound stator winding issurrounded by U-shaped soft iron cores (yokes), which are disposed inthe direction of rotation at the spacing of twice the pole pitch. Theopen ends of these U-shaped cores are aimed at an air gap between thestator and rotor and form the poles of the stator. Facing them,permanent magnets and concentrators are disposed in such a way that themagnets and concentrators that face the poles of a stator core have theopposite polarity. To short-circuit the permanent magnets, which in therotor rotation are intermittently located between the poles of thestator and have no ferromagnetic short circuit, short-circuit elementsare disposed in the stator.

Put otherwise, transverse flux electrical machines include a circularstator and a circular rotor, which are separated by an air space calledair gap, that allows a free rotation of the rotor with respect to thestator, and wherein the stator comprises soft iron cores, that directthe magnetic flux in a direction that is mainly perpendicular to thedirection of rotation of the rotor. The stator of transverse fluxelectrical machines also comprises electrical conductors, defining atoroid coil, which is coiled in a direction that is parallel to thedirection of rotation of the machine. In this type of machine, the rotorcomprises a plurality of identical permanent magnet parts, which aredisposed so as to create an alternated magnetic flux in the direction ofthe air gap. This magnetic flux goes through the air gap with a radialorientation and penetrates the soft iron cores of the stator, whichdirects this magnetic flux around the electrical conductors.

In the transverse flux electrical machine of the type comprising arotor, which is made of a plurality of identical permanent magnet parts,and of magnetic flux concentrators, the permanent magnets are orientedin such a manner that their magnetization direction is parallel to thedirection of rotation of the rotor. Magnetic flux concentrators areinserted between the permanent magnets and redirect the magnetic fluxproduced by the permanent magnets, radially towards the air gap.

The transverse flux electrical machine includes a stator, whichcomprises horseshoe shaped soft iron cores, which are oriented in such amanner that the magnetic flux that circulates inside these cores, isdirected in a direction that is mainly perpendicular to the axis ofrotation of the rotor.

The perpendicular orientation of the magnetic flux in the cores of thestator, with respect to the rotation direction, gives to transverse fluxelectrical machines a high ratio of mechanical torque per weight unit ofthe electrical machine.

It is desirable that the magnets and the concentrators of the rotor of atransverse flux electrical machine be precisely mounted on the rotor toensure a tight airgap with the stator portion when rotatably assembledwith the stator portion.

It is also desirable that the rotor portion be rotatably mounted to anaxial shaft with bearings and seals preventing any undesirable objectsor dirt to get into the rotor portion.

One other desirable aspect consists in providing as strong and secureassembly of the concentrators and the magnets to the body of the rotorportion to prevent any undesirable removal of a concentrator and/or amagnet when the transverse flux electrical machine is in operation.

At least one aspect of the present invention provides an external rotorassembly adapted to rotate around the stator assembly to increase theeffective airgap diameter while having a reduced overall stator androtor assembly or, for example, to have a rotative external component.

It is therefore desirable to produce an electrical machine that is easyto assemble. It is also desirable to provide an electrical machine thatis economical to produce. Other deficiencies will become apparent to oneskilled in the art to which the invention pertains in view of thefollowing summary and detailed description with its appended figures.

SUMMARY OF THE INVENTION

It is one aspect of the present invention to alleviate one or more ofthe shortcomings of background art by addressing one or more of theexisting needs in the art.

The following presents a simplified summary of the invention in order toprovide a basic understanding of some aspects of the invention. Thissummary is not an extensive overview of the invention. It is notintended to identify key/critical elements of the invention or todelineate the scope of the invention. Its sole purpose is to presentsome concepts of the invention in a simplified form as a prelude to themore detailed description that is presented later.

Generally, an object of the present invention provides a modularTransverse Flux Electrical Machine (TFEM), which can also be morespecifically appreciated as Transverse Flux Permanent Magnet (TFPM),which includes phase modules thereof.

An object of the invention is generally described as a modular TFEMincluding a plurality of phase modules adapted to be axially assembled.

Generally, an object of the invention provides a TFEM including a rotorportion rotatably assembled to a stator module and including a pluralityof phase modules axially assembled together with concentrators andmagnets of the plurality of phases axially aligned.

One object of the invention provides a rotor portion adapted to beaxially removed from its cooperating stator portion.

At least one object of the invention provides a rotor portion includingtwo opposed axial rotor support members having different diameters whichrespectively and removably accommodate a bearing allowing rotation ofthe rotor portion in respect with the stator portion.

At least one aspect of the invention provides a rotor portion includingan alternate series of concentrators and magnets chemically secured to arotatable non-magnetic frame and optionally further mechanically securedwith belts thereon.

At least one aspect of the invention provides a rotor portion havinginsulated shaft and magnets and concentrators supporting structure toprevent Foucault current to damage the bearing supporting the shaft.

At least one object of the invention provides a rotor portion assemblyincluding a magnets-and-concentrators supporting frame including aseries of adjacent groves, or slots, adapted to radially and angularlylocate the concentrators thereon.

At least one object of the invention provides a rotor portion assemblyincluding a magnets-and-concentrators supporting frame made ofnon-magnetic material.

At least one aspect of the invention provides a rotor portion assemblyincluding a rotatable supporting shaft shaped and designed tomechanically radially and axially locate a magnets-and-concentratorssupporting frame thereon.

At least one aspect of the invention provides a rotor portion assemblyincluding a magnets-and-concentrators supporting frame rotatablyconnected to a rotatable supporting shaft via at least one supportingplates including openings therein.

At least one aspect of the invention provides a method of assemblingconcentrators and magnets on a magnets-and-concentrators supportingframe including mechanically locating the concentrators on themagnets-and-concentrators supporting frame to bond the concentratorsthereon and then machine the exterior diameter of the concentratorsprior to assemble a magnet between two adjacent concentrators.

At least one object of the invention provides a tool adapted to locateand assemble at least one concentrator to a magnets-and-concentratorssupporting frame, the tool being adapted to simultaneously secure aplurality of concentrators for a multiple phase rotor portion.

At least one object of the invention provides a tool adapted to locateand assemble at least one concentrator to a magnets-and-concentratorssupporting frame, the tool being adapted to self locate with aconcentrator-receiving slot in a magnets-and-concentrators supportingframe to properly axially and radially locate concentrators in theconcentrator-receiving slot. A plurality of tool adapted to locate andassemble at least one concentrator to a magnets-and-concentratorssupporting frame can be used simultaneously.

At least one aspect of the invention provides a tool adapted to locateand assemble at least one concentrator to a magnets-and-concentratorssupporting frame, the tool being adapted to magnetically retainconcentrators therein to self locate each concentrator in aconcentrator-receiving space of the tool.

At least one other aspect of the present invention provides skewedmagnets and concentrators in an external rotor assembly.

At least one aspect of the present invention provides keystone shapedmagnets and concentrators.

At least one aspect of the present invention provides keystone shapedconcentrators cooperating with magnets having straight/parallel wallsand thus reduce the amount of magnet material.

At least one aspect of the present invention provides a rotatabletransverse flux electrical machine (TFEM) comprising a stator portionand a rotor portion operatively disposed inside the stator portion, therotor portion comprising a plurality of magnets and concentratorsalternatively affixed in a cylindrical arrangement to a non-magneticmagnets-and-concentrators supporting frame, the non-magneticmagnets-and-concentrators supporting frame being operatively secured toan axial shaft concentrically aligned with a rotational axis of therotor portion.

At least one aspect of the present invention provides a stator portionadapted to operatively cooperate with a stator portion of a rotatabletransverse flux electrical machine (TFEM), the rotor portion comprisinga plurality of magnets and concentrators alternatively affixed in acylindrical arrangement to a non-magnetic magnets-and-concentratorssupporting frame, the non-magnetic magnets-and-concentrators supportingframe being operatively secured to an axial shaft concentrically alignedwith a rotational axis of the rotor portion.

At least one aspect of the present invention provides a stator portionadapted to operatively cooperate with a stator portion of a rotatabletransverse flux electrical machine (TFEM), the rotor portion comprisinga plurality of axially disposed phases, each one of the phase comprisinga plurality of magnets and concentrators alternatively affixed in acylindrical arrangement to a supporting frame, the supporting framecomprising a series of axial concentrator-receiving portions and beingoperatively secured to an axial shaft concentrically aligned with arotational axis of the rotor portion.

Embodiments of the present invention each have at least one of theabove-mentioned objects and/or aspects, but do not necessarily have allof them. It should be understood that some aspects of the presentinvention that have resulted from attempting to attain theabove-mentioned objects may not satisfy these objects and/or may satisfyother objects not specifically recited herein.

Additional and/or alternative features, aspects, and advantages ofembodiments of the present invention will become apparent from thefollowing description, the accompanying drawings, and the appendedclaims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an isometric view of a TFEM in accordance with at least oneembodiment of the invention;

FIG. 2 is an isometric view of a TFEM in accordance with at least oneembodiment of the invention;

FIG. 3 is a left side elevational view of a TFEM in accordance with atleast one embodiment of the invention;

FIG. 4 is a right side elevational view of a TFEM in accordance with atleast one embodiment of the invention;

FIG. 5 is a top plan view of a TFEM in accordance with at least oneembodiment of the invention;

FIG. 6 is a bottom plan view of a TFEM in accordance with at least oneembodiment of the invention;

FIG. 7 is a rear elevational view of a TFEM in accordance with at leastone embodiment of the invention;

FIG. 8 is a front elevational view of a TFEM in accordance with at leastone embodiment of the invention;

FIG. 9 is a section view of a TFEM illustrating multiple phase modulesin accordance with at least one embodiment of the invention;

FIG. 10 is an isometric semi-exploded view of a TFEM illustrating astator portion and a rotor portion in accordance with at least oneembodiment of the invention;

FIG. 11 is an isometric semi-exploded view of a portion of a TFEMillustrating a rotor portion in accordance with at least one embodimentof the invention;

FIG. 12 is an isometric semi-exploded view of a TFEM illustrating arotor portion in accordance with at least one embodiment of theinvention;

FIG. 13 is a section view of the rotor portion of a TFEM in accordancewith at least one embodiment of the invention;

FIG. 14 is a magnified section view of the stator portion of the TFEM inaccordance with at least one embodiment of the invention;

FIG. 15 is a magnified section view of the stator portion of the TFEM inaccordance with at least one embodiment of the invention;

FIG. 16 is a front elevation view of the rotor in accordance with atleast one embodiment of the invention;

FIG. 17 is a sectional front elevation view of the rotor in accordancewith at least one embodiment of the invention;

FIG. 18 is a sectional view of a portion of the magnets andconcentrators assembly in accordance with at least one embodiment of theinvention;

FIG. 19 is an isometric view of a concentrator in accordance with atleast one embodiment of the invention;

FIG. 20 is an isometric view of a magnet in accordance with at least oneembodiment of the invention;

FIG. 21 is an isometric view of a concentrator support in accordancewith at least one embodiment of the invention;

FIG. 22 is an isometric view of a concentrator support in accordancewith at least one embodiment of the invention;

FIG. 23 is an isometric view of a concentrator support in accordancewith at least one embodiment of the invention;

FIG. 24 is an isometric view of a concentrator support in accordancewith at least one embodiment of the invention;

FIG. 25 is an isometric view of concentrator supports in conjunctionwith a rotor element in accordance with at least one embodiment of theinvention;

FIG. 26 is a front elevation view of concentrator supports inconjunction with a rotor element in accordance with at least oneembodiment of the invention;

FIG. 27 is a sectional front elevation view of concentrator supports inconjunction with a rotor element in accordance with at least oneembodiment of the invention;

FIG. 28 is an exemplary flow chart of steps for assembling concentratorson a rotor assembly in accordance with at least one embodiment of theinvention;

FIG. 29 is an isometric view of a schematic layout of magnets andconcentrators for an external rotor portion in accordance with at leastone embodiment of the invention;

FIG. 30 is an isometric view of a schematic layout of magnets andconcentrators for an external rotor portion in accordance with at leastone embodiment of the invention;

FIG. 31 is a schematic front elevation view of a series of magnets andconcentrators in accordance with at least one embodiment of theinvention;

FIG. 32 is a schematic front elevation view of a series of magnets andconcentrators in accordance with at least one embodiment of theinvention; and

FIG. 33 is an exemplary series of steps for assembling an externalstator.

DESCRIPTION OF EMBODIMENT(S) OF THE INVENTION

Our work is now described with reference to the Figures. In thefollowing description, for purposes of explanation, numerous specificdetails are set forth in order to provide a thorough understanding ofthe present invention by way of embodiment(s). It may be evident,however, that the present invention may be practiced without thesespecific details. In other instances, when applicable, well-knownstructures and devices are shown in block diagram form in order tofacilitate describing the present invention.

The embodiments illustrated below depict a TFEM 10 with thirty-two (32)poles and a 510 mm diameter at the air gap and a 100 mm length of themagnets. The configuration of the TFEM 10, an external rotor instead ofan internal rotor, the number of phases can change in accordance withthe desired power output, torque and rotational speed without departingfrom the scope of the present invention.

A TFEM 10 is illustrated in FIG. 1 through FIG. 8. The TFEM 10 includesa stator portion 14 and a rotor portion 18. The stator portion 14 isadapted to remain fixed while the rotor portion 18 is located within thestator portion 14 and is adapted to rotate in respect with the statorportion 14 about rotation axis 22. The TFEM of the illustratedembodiments has a modular construction. Two axial side members 26 aresecured together to assemble three electrical phases 30 together, eachbeing provided by a phase module 32. Each phase module 32 is adapted toindividually provide an electrical phase 30 of alternating current. Thepresent embodiment illustrates three phases 30 axially coupled togetherto provide tri-phased current when the TFEM 10 is rotatably actuated.The pair of axial side members 26 interconnects and axially securestogether the three phases 30. Proper tension is applied to each of theplurality of axial securing members 34 to ensure the phase modules 32remain fixedly secured together. In the present embodiment, each axialside member 26 is provided with a series of extending axial securingmember receiving portions 38 adapted to receive the axial securingmembers 34 therein while the axial securing members 34 extends axiallyoutside the phase modules 32. The axial securing members 34 couldalternatively pass through the phase modules 32 in another unillustratedembodiment.

Still referring to FIG. 1 through FIG. 8, the axial side members 26 canbe made of steel or other suitable material providing sufficientmechanical strength for the required purpose. Each axial side members 26is optionally provided with a lifting link 42 sized and designed toreceive therein, for example, a crane hook (not illustrated) to lift andmove the TFEM 10. The axial side members 26 are further equipped with asupport portion 46 adapted to secured thereto a pair of feet 50configured to interconnect both axial side members 26 together and tofurther facilitate securing the TFEM 10 to a base chassis (notillustrated). For instance, the base chassis can be a nacelle when theTFEM 10 is installed in a windmill or alternatively any other chassisprovided by the equipment the TFEM 10 is operatively connected to.

Each axial side member 26 is configured to receive and secure thereto anaxial rotor support member 54. The axial rotor support member 54 isrecessed in a circular cavity 56 (visible in FIG. 9) defined in itsassociated axial side member 26 to concentrically locate the rotorportion 18 in respect with the stator portion 14. The axial rotorsupport member 54 is further removably secured to its associated axialside member 26 with a plurality of fasteners 58. The actualconfiguration of the embodiment illustrated in FIG. 9 allows removal ofthe rotor portion 18 in one axial direction 60 when both axial rotorsupport members 54 are unsecured from their respective axial side member26 because the circular cavities 56 are both located on the same side oftheir respective axial side member 26. This allows for easy maintenanceof the TFEM 10 once installed in its operating configuration with itsexternal mechanism.

As it is also possible to appreciate from the embodiment illustrated inFIGS. 1 through 8, the rotor portion 18 extends through the axial rotorsupport members 54 and rotatably engages both axial rotor support member54. A solid rotor drive member 62 further extends from one axial rotorsupport members 54. The solid drive member 62 could alternatively be ahollowed drive member in another unillustrated embodiment. The drivemember 62 is adapted to transmit rotatable motive power from an externalmechanism (not illustrated) to the TFEM 10 and includes a drive securingmechanism 66 adapted to rotatably couple the drive member 62 of the TFEM10 to a corresponding rotatable drive element from the externalmechanism (not illustrated). The external mechanism (not illustrated)could, for example, be a windmill rotatable hub (not illustrated) towhich the rotor blades (not illustrated) are secured to transmitrotational motive power to the TFEM 10. The external mechanism expressedabove is a non-limitative example and other external mechanisms adaptedto transmit rotational motive power to the TFEM 10 are considered toremain within the scope of the present application.

The TFEM 10 is further equipped with a protective plate 70 adapted tostore and protect electrical connectors and electrical wires thatextends from the TFEM 10 through an electrical outlet 74.

A section view of the TFEM 10 is illustrated in FIG. 9. The rotorportion 18 includes a cylindrical frame 122 preferably removably securedto the rotatable drive member 62 with a series of fasteners 128, andassociated nuts 132, via two plates 124 radially extending from thedrive member 62. As explained above, the cylindrical frame 122 is sizedand designed to accommodate three electrical phases 30, each provided bya phase module 36 including its alternate series of magnets 94 andconcentrators 98 secured thereon. The circular stator portion 14 and thecircular rotor portion 18 are separated by an air space called “air gap”126 that allows an interference-free rotation of the rotor portion 18with respect to the stator portion 14. Generally, the smaller is the airgap 126 the more performance the TFEM is going to provide. The air gap126 is however limited to avoid any mechanical interference between thestator portion 14 and the rotor portion 18 and is also going to beinfluenced by manufacturing and assembly tolerances in addition tothermic expansion of the parts when the TFEM 10 is actuated. The statorportion 14 comprises soft iron cores (cores) 130 that direct themagnetic flux in a direction that is mainly perpendicular to thedirection of rotation of the rotor portion 18. The stator portion 14 ofTFEM 10 also comprises in each phase module 32 electrical conductorsdefining a toroid coil 134 that is coiled in a direction that isparallel to the direction of rotation of the TFEM 10. In thisembodiment, the rotor portion 18 comprises a plurality of identicalpermanent magnets 94, which are disposed so as to create an alternatedmagnetic flux in the direction of the air gap 126. This magnetic fluxgoes through the air gap 126 with a radial orientation and penetratesthe soft iron cores 130 of the stator portion 14, which directs thismagnetic flux around the toroid coil 134.

In the TFEM 10 of the type comprising a rotor portion 18 including aplurality of identical permanent magnets 94 and of magnetic fluxconcentrators 98, the permanent magnets 94 are oriented in such a mannerthat their magnetization direction is parallel to the direction ofrotation of the rotor portion 18, along rotation axis 22. Magnetic fluxconcentrators 98 are disposed between the permanent magnets 94 andredirect the magnetic flux produced by the permanent magnets 94 radiallytowards the air gap 126. In contrast, the stator portion 14 comprises“horseshoe-shaped” soft iron cores 130, which are oriented in such amanner that the magnetic flux that circulates inside these cores 130 isdirected in a direction that is mainly perpendicular to the direction ofrotation of the rotor portion 18. The perpendicular orientation of themagnetic flux in the cores 130 of the stator portion 14, with respect tothe rotation direction, gives to TFEM a high ratio of mechanical torqueper weight unit of the electrical machine.

Turning now to FIG. 10 illustrating a semi-exploded TFEM 10 where askilled reader can appreciate the depicted rotor portion 18 is axiallyextracted 60 from the stator portion 14. The rotor portion 18 is axiallyextracted 60 from the stator portion 14 by removing the plurality offasteners 58 and unsecuring the axial rotor support members 54 fromtheir respective associated axial side member 26. It can be appreciatedthat the rotor portion 18 of the exemplary embodiment has three distinctmodular phases 36, each providing an electrical phase 30, adapted toaxially align and operatively cooperate with the three phase modules 32of the exemplified stator portion 14.

FIG. 11 illustrates a further exploded view of the rotor portion 18. Asindicated above, the rotor portion 18 is adapted to rotate in respectwith the stator portion 14. The speed of rotation can differ dependingof the intended purpose. Power remains function of the torque and therotation speed of the rotor portion 18 therefore the TFEM is going toproduce more power if the TFEM rotates rapidly as long as its operatingtemperature remains in the operating range of its different parts toprevent any deterioration (e.g. magnet demagnetization or insulatingvarnish deterioration, to name a few. The axial rotor support members 54are adapted to be unsecured from the bearing holder 78 by removing theplurality of fasteners 82. A sequence of assembled seal 86, bearing 90and bearing holder 78 is used on the front side of the rotor portion 18while the same type of assembly is used on the opposite axial side ofthe rotor portion 18 to rotatably secure the rotor 80 to the axial rotorsupport members 54. FIG. 11 also illustrates that each phase module 36of the rotor 80 uses a sequence of alternating permanent magnets 94 andconcentrators 98. Strong permanent magnets 94 can be made of Nb—Fe—B asoffered by Hitachi Metals Ltd and NEOMAX Co. Ltd. Alternatively,suitable magnets can be obtained by Magnequench Inc. and part of thistechnology can be appreciated in U.S. Pat. No. 5,411,608, U.S. Pat. No.5,645,651, U.S. Pat. No. 6,183,572, U.S. Pat. No. 6,478,890, U.S. Pat.No. 6,979,409 and U.S. Pat. No. 7,144,463.

The axial rotor support members 54 are disassembled from the rotorportion 18 in the semi-exploded view of the rotor portion 18 in FIG. 11.The axial rotor support members 54 are preferably made of a materialthat is mechanically strong enough to sustain the mechanical loadsapplied thereon when the TFEM 10 is assembled and in operation. Theaxial rotor support members 54 illustrated in the embodiments of FIG. 11are round to facilitate the axial alignment of the rotor portion 18 withthe stator portion 14 when the axial rotor support members 54 aresecured to the axial side members 26. Each axial rotor support members54 accommodates a bearing assembly including a seal 86 preventingforeign material to enter the TFEM 10 assembly. The seal 86 is pressedfitted into an opening sized and designed accordingly in the axial rotorsupport members 54. A series of fasteners 82 are disposed in a boltcircle on the axial rotor support members 54 to secure on the interiorside of the axial rotor support members 54 a bearing holder 78 adaptedto receive therein a bearing 90. The bearing 90 supports the drivemember 62 in a rotatable fashion to allow rotation of the rotatableelements of the rotor portion 18 in respect with the stator portion 14.

FIG. 12 and FIG. 13 illustrate in greater details rotatable elements ofthe embodied rotor portion 18. A skilled reader will notice that eachphase 30 of the three illustrated phases 36 of the rotor portion 18include a respective series of radially alternated magnets 94 andconcentrators 98. The series of magnets 94 and concentrators 98 areevenly distributed in a cylindrical shape about and at substantially thesame radial distance from the rotation axis 22. The series of magnets 94and concentrators 98 are supported by a cylindrical frame 122 includinga series of sixty four (64) parallel grooves 138 therein to locate themagnets 94 and concentrators 98 at their desired positions. Differentconfigurations of TFEM 10 are possible and the number of grooves 138 canbe adjusted accordingly. The cylindrical frame 122 is made of anon-magnetic material to prevent any undesirable magnetic interferencebetween the magnets 94 and the concentrators 98. For instance, thecylindrical frame 122 of the present embodiment is made of aluminum forthe reason expressed above, for its light weight and also becausealuminum is a good conductor to carry heat. The cylindrical frame 122 isconnected to the drive member 62 with a pair of plates 124 also made ofnon-magnetic material. The plates 124 are preferably removably securedto the drive 62 via a circular flange 166. The circular flange isabutted on a shoulder portion 170 provided on the drive 62 to preventthe flanges 166 to axially move in respect to one another. An axialgroove 174 is performed in the drive 62 to receive therein a key member178 adapted to lock relative rotational movements of the plates 124 andthe cylindrical frame 122 about the drive 62. In so doing, rotationaland longitudinal movements can be temporarily secured prior welding thecircular flange 166 and the key member 178 to the drive 62. The plates124 and the cylindrical frame 122 are then permanently positioned andsecured about the drive 62. I can become apparent to a skilled readerthat other ways of securing the cylindrical frame 122 to the drivemember 62 are possible and remain within the scope of the presentinvention.

The concentrators 98 are first secured to the cylindrical frame 122 witha bonding material 150. Strong industrial adhesive 150, such as Loctite9432 NA, applied and cured properly, is recommended although othersecuring means can be used without departing from the present invention.More details regarding the method for installing the magnets 94 and theconcentrators 98 are going to be provided later. The cylindrical frame122 and the concentrators 98, once the adhesive 150 has cured and theconcentrators 98 are firmly secured to the cylindrical frame 122, areturned on a lathe to bring the diameter of the overall assembly to adesired dimension for ensuring a tight airgap 126 when assembled to thecooperating stator portion 14. The correction of the overall diameter ismade prior to installing the magnets 94 between the concentrators 98 toprevent magnetically collecting the metallic residues created in theprocess of turning the cylindrical frame 122 and the concentrators 98assembly. The magnets 94 are then simply inserted between theirrespective adjacent concentrators 98 in a first embodiment and only aremaintained in place by the magnetic attraction to the concentrators 98.Industrial adhesive 150 can be used to further secure the magnets 94 ina similar fashion between the concentrators 98. The height of themagnets 94 is generally smaller than the height of the concentrators 98and do not exceed the height of the latter thus do not need to bemachined on a lathe. This also saves valuable ferromagnetic material.

Non-magnetic belts 142 are further mechanically securing theconcentrators 98 to ensure they remain in place on the cylindrical frame122. The belts 142 can be made of a stainless steel coil winded over thelateral shoulder extremities of the concentrators 98. The belts 142 arepreferably not contacting the magnets 94 to limit the amount of magnetmaterial, that is expensive, and because the magnet material isgenerally mechanically weak and would risk breaking under the forceapplied by the belts 142.

Still referring to FIG. 12 and FIG. 13, one can appreciate that thebearings 90 are respectively secured by a bearing holder 154 tighten andsecured by an array of fasteners 158. It is clearly visible from FIG. 13that the axial rotor support members 54 are not of similar diameters.The axial rotor support member 54 on the front of the rotor portion 18has a larger diameter than the axial rotor support member 54 on the rearside of the rotor portion 18 to allow axial extraction of the rotorportion 18 from the stator portion 14. Extraction would be impossiblewithout removing the rear axial rotor support member 54 from the drivemember 62 should both axial rotor support members 54 be the samediameter. One can also appreciate the indentations 162 used to axiallylocalize the rotor portion 18 in respect with the stator portion 14 aredisposed on the same side of their respective axial rotor support member54.

FIG. 14 illustrates in greater details the bearing assembly of the rotorportion 18 located on the front side of the TFEM 10. One can appreciatethat the bearing 90 is electrically insulated, with an insulating member182, from the other parts to prevent any electrical current transferbetween the drive 62, and its associated rotating parts, and the axialrotor support member 54, and its associated fixed parts. Foucaultcurrents and currents created by high transient voltage are thusinsulated hence preventing the bearings 90 to be a means to transfercurrent and possibly be sparked thus likely reducing their useful lifeexpectancy. The insulating material used in the illustrated embodimentis a sheet material sold by Protectolite Inc. under the code GPO-3.Petrolite GPO-3 is an electrical grade sheet manufactured under highheat and pressure in matched metal moulds and are excellent fire andtrack resistant, and meets NEMA Standards. Other suitable mechanicallystrong and insulating materials could be used without departing from thescope of the present invention. One can appreciate from FIG. 15 that asimilar assembly secures the bearing assembly of the rotor portion 18located on the rear side of the TFEM 10.

Moving now to FIG. 16 illustrating a front elevation view of therotatable parts of the rotor portion 18. One can appreciate the plate124 includes a cut portion 186 adapted to allow the passage therethroughof the key member 178, once the key member 178 is permanently assembledto the drive 62, to be able to disassemble the drive 124 from the pairof plates 124. An array of openings 190 are present in the plates 124for lighten the rotatable parts and to allow air exchange between thedifferent parts of the assembly. FIG. 17 is a section view of therotatable parts illustrated in FIG. 17. One skilled in the art canappreciate the array of magnets 94 and concentrators 98 disposed aboutthe rotation axis 22. Further magnified, a portion of the magnets 94 andconcentrators 98 layout is shown in FIG. 18 where a space 194 filledwith adhesive 150. FIG. 18 is illustrates a magnified portion of theassembly in FIG. 17.

A concentrator 98 made of soft magnetic material is illustrated in FIG.19. The concentrator 98 embodied in the present invention includes two(2) recessed portions 200 adapted to accommodate the belt 142 identifiedabove. Concentrators have an axial length 204, a radial height 208 and awidth 212 sized and designed to meet the performance criterion of theTFEM 10. Different concentrator's 98 proportions are contemplated in thescope of the present invention. The axial length 216 without therecessed portions 200 is generally of the same length as the magnets 94that is going to be illustrated in FIG. 20, to prevent, inter alia, tocontact the belt 142 that is preferably only contacting theconcentrators 98. In turn, FIG. 20 depicts a typical magnet 94 that hasan axial length 220, a radial height 224 and a width 228. The magnet 94typically has two angled β sides 232 adapted to cooperate with thesidewalls of the adjacent concentrators 98 given the radial distributionof the concentrators 98 leaving a “V” shaped gap therebetween.

One of the significant aspects of the rotor portion 18 assembly is thepositioning of the concentrators 98 and the magnets 94. Theconcentrators 98 are of significant influence because they are installedfirst on the cylindrical frame 122. As mentioned above the concentrators98 of embodiments of the invention are secured with an adhesive andtheir respective positioning has to be standardized to prevent too manydiscrepancies between them that would jeopardize the global assembly.The concentrators 98 need to be axially aligned with the rotation axis22 and at substantially the same radial distance from the rotation axis22. One possible way to achieve that is to clean and prepare thesurfaces of the cylindrical frame 122 and the concentrators 98 prior toapply adhesive on the cylindrical frame 122. A jig 240 adapted toposition a row of three (3) concentrators 98 is illustrated in FIG. 21and FIG. 22—we have a row of three (3) concentrators 98 because theillustrative embodiment is a three (3) phase TFEM 10, one concentrator98 per phase.

The jig 240 illustrated in FIG. 21 has three (3) concentrator-receivingspaces 244 included in a frame 248 and to properly interact andsimultaneously secure three (3) concentrators 98 on the cylindricalframe 122—that is the base of a three (3) phases rotor portion 18. Theconcentrator-receiving spaces 244 are equidistantly disposed in thisembodiment of the frame 248 and laterally bordered by two opposed wallportions 250 to locate the concentrators 98 in their respectiveconcentrator-receiving space 244. The frame 248 uses the cylindricalframe 122 as a reference and includes a first pair of reference surfaces252 adapted to contact the exterior of the cylindrical frame 122 and asecond pair of reference surfaces 256 opposed to the first pair ofreference surfaces 252 adapted to contact the interior surface of thecylindrical frame 122. The second pair of reference surfaces 256 islocated on an adjustable member 260 adapted to be tighten toward thefirst pair of reference surfaces 252 to secure the frame 248 to thecylindrical frame 122 hence locating the concentrators 98 containedtherein. Each adjustable member 260 is guided in an axial direction 264by a dowel pin 268 and a fastener 272 to ensure the adjustable member260 remains aligned in the axial direction 264 while allowing someadjustment in this direction. The fastener 272 serves to secure the jig240 to the cylindrical frame 122 once the jig 240 is properly located inrespect with a series of adjacent and parallel slots 264 disposed on thecylindrical frame 122. The slots 264 are means to angularly locate theconcentrators 98 on the cylindrical frame 122 so that the concentratorsare equidistantly disposed on the cylindrical frame 122 about therotation axis 22. One can appreciate from FIG. 18 that the slots 264 arecreating intervening ridges 268 used to angularly space apart adjacentconcentrators 98. The diameter of the cylindrical frame 122 and thedepth of the slots 264 are sized and designed to correctly radiallylocate each concentrator 98, with an adequate intervening adhesive 150,to obtain the desired end diameter to engage the stator portion 14 andobtain the desired airgap 126 therebetween.

FIG. 22 illustrate a first step of assembling the concentrators 98inside their respective concentrator receiving space 244 by insertingeach concentrator 98 between the wall portions 250. FIG. 23 illustratethe jig 240 with three concentrators 98 assembled in the threeconcentrator-receiving spaces 244. Moving now to FIG. 24 depicting asection view of a jig 240 with three concentrators 98 disposed therein.One can clearly appreciate the first pair of reference surface 252 andthe second pair of reference surface 256 adapted to radially locate andsecure the jig 240 to the cylindrical frame 122 as explained above. Afurther axial pair of reference surfaces 276 is illustrated and is usedto axially locate the jig 240 on the cylindrical frame 122, as it willbe seen in FIG. 24. Remaining with FIG. 23, one can appreciate aplurality of magnets 280 press-fitted in the frame 248 of the jig 240 tohold each concentrator 98 in their respective concentrator-receivingspaces 244. This is one illustrative way to temporarily secure theconcentrators 98 in their respective concentrator-receiving space 244that is convenient because the jig 240 can simply be removed from thecylindrical frame 122 once the concentrators 98 are secured to thecylindrical frame 122 when the adhesive 150 between the concentrators 98and the cylindrical frame 122 is cured. One additional feature can beappreciated from FIG. 24. An axial reference edge 284 is defined in thejig 240 for axially locating each concentrator 98. The axial positioningof each concentrator 98 is thus made by inserting a concentrator 98 inits concentrator-receiving space 244, that is axially longer than theactual axial length of a concentrator 98, and moving the concentrator 98in the axial direction 288 to abut a wall portion 202 of the recessedportion 200 of the concentrator 98 to the axial reference edge 284. Thisway, each concentrator 98 is axially referenced on the same axial sideto ensure consistent location of the concentrators 98.

A cylindrical frame 122 is depicted in FIG. 25 through FIG. 27. Thecylindrical frame 122 is illustrated with a plurality of jigs 240assembled thereon. A single jig 240 or a plurality of jig 240 can besimultaneously assembled to the cylindrical frame 122. The area coveredby adhesive 150 can be a factor influencing the number of jig 240 to beinstalled simultaneously to prevent curing adhesive in slots 264 wherethere is no concentrators 98.

FIG. 28 illustrates an exemplary series of steps that can be used toassemble the magnets 94 and the concentrators 98 to the rotatablecylindrical frame 122.

The previous embodiments illustrated an internal rotor portion 18intended to operate in conjunction with an external stator portion 14.The internal rotor portion 18 is adapted to rotate inside the statorportion 14. One could appreciate from the figures that the externalstator portion 14 has a significant radial thickness on the distal sideof the airgap. An external rotor portion 300 can be desirable when theoverall external diameter of the TFEM 10 should be kept to a minimumbecause the radial thickness of the rotor portion 300 is generallysmaller than the radial thickness of the stator portion 14. Forinstance, generators and motors applications like an electricwheel-motor, windmills where blades are connected to the external rotor,and fans where blades are connected to the external rotor portion 300.An example is schematically illustrated in FIGS. 29 and 30. One canappreciate the external rotor 300 has also an alternate series ofmagnets 94 and concentrators 98. The magnets 94 and concentrators 98 aretemporarily mounted on a cylindrical support 304 prior to be insertedand secured in an external frame 308. The cylindrical support 304 isadapted to locate and maintain the magnets 94 and concentrators 98 toensure proper positioning inside the external frame 308. Once themagnets 94 and concentrators 98 are properly positioned on thecylindrical support 304 the assembly is optionally machined to ensure acylindrical exterior shape with proper diameter. Then the cylindricalsupport 304 with the magnets 94 and the concentrators 98 are axiallyslided in the external frame 308. The interior wall portion of theexternal frame 308 is coated with an adhesive prior to receive themagnets 94 and concentrators 98 assembly to permanently secure themagnets 94 and concentrators 98 properly in place in an operatingconfiguration inside the external frame 308.

Once the adhesive has cured and the magnets 94 and the concentrators 98are firmly secured inside the external frame 308, the external rotor 300assembly is machined to bring the internal diameter of the magnets 94and concentrators 98 to a desired dimension to ensure proper radius ofthe radially proximal surfaces of the magnets 94 and concentrators 98and also ensure the airgap between the stator portion 14 (notillustrated in FIGS. 29, 30) and the rotor portion 300 is optimal.Alternatively, the magnets 94 and concentrators 98 are secured by resininjection in the external frame 308.

The external rotor 300 can accommodate thereon a plurality of skewed 312magnets 94 and concentrators 98 in respect with the rotation axis 22 ofthe rotor portion 28, 300. Skewed 312, or angled magnets 94 andconcentrators 98, allows a more progressive interaction between themagnets 94 and concentrators 98 and the cooperating cores in the statorportion 14.

Moreover, the shape of the magnets 94 and concentrators 98 thatcooperates together can all be the same as schematically illustrated inFIG. 31. The magnets 94 and concentrators 98 all have a “keystone”trapezoidal shape. The keystone shape 316 helps mechanically self locateand support the magnets 94 and concentrators 98 in the rotor 300.Conversely, as schematically illustrated in FIG. 32, because the magnetsmaterial is generally more difficult to machine, or alter, and becausethe magnet material is expensive, the shape of the magnets 94 can bemore standard, like rectangular, and the shape of the concentrators 98is a more pronounced “keystone” shape adapted to take on the remainingspace of the straight magnets 94. The self-locating and self-supportingkeystone effect is thus realized by shaping in keystone shape only theconcentrators 98. This is one way to use less magnet material and reducethe cost of the TFEM 10.

FIG. 33 illustrates an exemplary series of steps that can be used toassemble the magnets 94 and the concentrators 98 to the external rotor300.

The description and the drawings that are presented above are meant tobe illustrative of the present invention. They are not meant to belimiting of the scope of the present invention. Modifications to theembodiments described may be made without departing from the presentinvention, the scope of which is defined by the following claims:

What is claimed is:
 1. A rotatable transverse flux electrical machine(TFEM) comprising a stator portion and a rotor portion operativelydisposed inside the stator portion, the rotor portion comprising aplurality of magnets and concentrators alternatively affixed in acylindrical arrangement to a non-magnetic magnets-and-concentratorssupporting frame, the non-magnetic magnets-and-concentrators supportingframe being operatively secured to an axial shaft concentrically alignedwith a rotational axis of the rotor portion.
 2. The rotatable transverseflux electrical machine of claim 1, wherein themagnets-and-concentrators supporting frame comprises a series ofadjacent slots adapted to radially and angularly locate theconcentrators thereof.
 3. The rotatable transverse flux electricalmachine of claim 1, wherein the stator portion comprises a plurality ofaxially adjacent phases respectively comprising a plurality of magnetsand concentrators.
 4. The rotatable transverse flux electrical machineof claim 3, wherein concentrators of adjacent phases are axiallyaligned.
 5. The rotatable transverse flux electrical machine of claim 1,the axial shaft being rotatably secured to a pair of opposed axial rotorsupport members removably secured to respective axial side plates, theaxial rotor support members having different diameters to axially removethe rotor portion from the stator portion, the axial rotor supportmembers being respectively secured to a pair of bearings allowingrotation of the rotor portion in respect with the stator portion.
 6. Therotatable transverse flux electrical machine of claim 5, wherein adiameter of one of the endplate is smaller than an airgap of therotatable transverse flux electrical machine.
 7. The rotatabletransverse flux electrical machine of claim 1, wherein the rotor portionis insulated from the stator portion to prevent Foucault current betweenthe rotor portion and the stator portion.
 8. The rotatable transverseflux electrical machine of claim 1, wherein the magnets andconcentrators are keystone shaped.
 9. The rotatable transverse fluxelectrical machine of claim 1, wherein the concentrators are keystoneshaped and are cooperating with magnets having straight/parallel walls.10. A stator portion adapted to operatively cooperate with a statorportion of a rotatable transverse flux electrical machine (TFEM), therotor portion comprising a plurality of magnets and concentratorsalternatively affixed in a cylindrical arrangement to a non-magneticmagnets-and-concentrators supporting frame, the non-magneticmagnets-and-concentrators supporting frame being operatively secured toan axial shaft concentrically aligned with a rotational axis of therotor portion.
 11. The stator portion of claim 10, wherein themagnets-and-concentrators supporting frame comprises a series ofadjacent slots adapted to radially and angularly locate theconcentrators thereof.
 12. The stator portion of claim 10, wherein thestator portion comprises a plurality of axially adjacent phasesrespectively comprising a plurality of magnets and concentrators. 13.The stator portion of claim 12, wherein concentrators of adjacent phasesare axially aligned.
 14. The stator portion of claim 10, the axial shaftbeing rotatably secured to a pair of opposed axial rotor support membersremovably secured to respective axial side plates, the axial rotorsupport members having different diameters to axially remove the rotorportion from the stator portion, the axial rotor support members beingrespectively secured to a pair of bearings allowing rotation of therotor portion in respect with the stator portion.
 15. The stator portionof claim 14, wherein a diameter of one of the endplate is smaller thanan airgap of the rotatable transverse flux electrical machine.
 16. Thestator portion of claim 10, wherein the rotor portion is insulated fromthe stator portion to prevent Foucault current between the rotor portionand the stator portion.
 17. The stator portion of claim 10, wherein themagnets and concentrators are keystone shaped.
 18. The stator portion ofclaim 10, wherein the concentrators are keystone shaped and arecooperating with magnets having straight/parallel walls.
 19. A statorportion adapted to operatively cooperate with a stator portion of arotatable transverse flux electrical machine (TFEM), the rotor portioncomprising a plurality of axially disposed phases, each one of the phasecomprising a plurality of magnets and concentrators alternativelyaffixed in a cylindrical arrangement to a supporting frame, thesupporting frame comprising a series of axial concentrator-receivingportions and being operatively secured to an axial shaft concentricallyaligned with a rotational axis of the rotor portion.
 20. The statorportion of claim 19, wherein the magnets are contacting adjacentconcentrators and are radially distanced from the supporting frame.